I. Field
The present invention relates generally to wireless communication networks, and more specifically to precoding multicarrier waveforms.
II. Background
The background description includes information that may be useful in understanding the present inventive subject matter. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed inventive subject matter, or that any publication, specifically or implicitly referenced, is prior art.
The most pressing need in mobile wireless wide area networks (WWANs), such as cellular networks, is to meet the increasing demand for data services. However, only a very small portion of the radio spectrum is suitable for WWAN communications. Above a few Gigahertz, path losses become too great for wide area communications in typical terrestrial environments. Only a fraction of the suitable spectrum is allocated for WWANs, and those allocations are divided among (ostensibly) competing cellular companies.
Various techniques have been proposed to enable more efficient use of the available spectrum, such as spectrum sharing, dynamic bandwidth exchange, and various “smart” radio schemes. Other techniques, such as joint scheduling and power control, can improve frequency reuse in cell configurations. Carrier aggregation simply allocates more radio channels to each client device without improving spectrum efficiency, providing a temporary increase in data services until those channels become congested.
While such techniques can provide more efficient use of the available WWAN spectrum, the laws of Physics still dictate a limit to the amount of information that can be carried with a given amount of WWAN spectrum and power. Unfortunately, demand for data bandwidth continues to grow, irrespective of the limitations imposed by Physics.